Selective signaling system.



tion and adapted for selectively operating UNITED OFFICE.V

JOHN ERICKSDN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 FIRST TRUST AND SAVINGS BANK, TRUSTEE, OF CHICAGO, ILLINOIS.

SELEGTIVE SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Feb. 14, 1911.

Application filedAugnst 1E, 1905. Serial No. 274,492.

have invented a certain new and useful Ifnpi'ovement in Selective Signaling Systems, of which the following is a specification.

My invention relates to selective signaling systems in general, but more particularly to selective signaling systems adapted for use in connect-ion with party-line tele phone systems, and especially to selective signaling systems in which alternating electric currents are employed for selectively operating a plurality of signal-receiving means over the saine line. l My `invention contemplates the provision of certairf improvements generally; but as there are several features-v Which are disclosed and covered in my previous applic. tion Serial No. 274,491, iled August 16, 1905, it Will be seen that my present invention is also more or less in the nature of an improvement upon the selective signaling system shown and described in my said prior application.

vGenerally stated, the object of my invention is to provide an improved and highly eiiicient selective signaling system.

Special objects of my invention are to provide aniinproved construction and arrangement involvinga plurality of electric Vbells orv ringers connected with the same linecircuit, together with double-Wound rev -laysfor controlling normallyclosed shunts or short-circuitin connections extending around the said be ls or rifigers, and a calling apparatus arranged at thecentral stathe said bells or fingers; to provide an improved construction and whereby the establishment of the particuf lar line-circuit for ringing any givenbell or ringer serves also to automatically open the normally-closed shunt vor short-circuit ing connection extending around said bell or ringer, and whereby the similar connec# tions extending aroundA all other bells or ringers remain closed, thus insuring the def sred selective and non-interfering character 'ot'Vi'ho system; and to provide certain details and features of improvement tending to increase the general efiiciency and serv arrangement iceabilitv of a selective signaling system of this particular character.

ln the accompanying drawings, Figure 1 is a diagram illustrating a selective signaling system embodying the principles ot my invention,y and showing a party-line having four telephone subscribers7 stations thereon, together with the operators selective calling apparat-us at the exchange. or central` station. Fig. .2 is an enlarged detail view of one of the double-Wound relays with which .each subscribers apparatus is equipped, and

which control the shunt or short-circuiting connections extending around the different bells.

As thus illustrated, the construction and mode of operation of my invention are as follows: The several subscribers stations A, B, C and D are each provided with a polarized ringer 2, 3, 4; and 5, respectively; vand said stations, inr the order named, are each provided in'addition with two condensers 6 and 7, 8 and 9, l0 and 11, and 12 and 13, and with a double Wound magnet 14, 15, 16 and 17, respec tively, each of said magnets being provided With two polepieces 18 and 19, 20 and 21, 22 and 23, and 24 and 25, re spectively, and an armature 26, 27, 28 and 29, respectively. Each of said ringers 2, 3, 4 and 5, in the order named, is short-circuited through tvv-o springs 30 and 3l, 32 and 33, 34: and 35, and Elli and 37, respectively. Betvveen. each of the armatures 26,

27, 28 and 29, and one of the corresponding sponding short-circuiting spring at proper times. VEach line in the system terminates -in a jack, such as the jacks L12, 43 and 44. The stations arc designed that by press-l ing any one oil the pushsbuttons 45, 4:6, 47 and 4S, while the plug L19 is connected with any particular line-.thc line leading tothi,

vsub-station A, B, (l, and D, for example-- sonic one of the four stations on said line will be signaled.4 That. is, the arrangement is such that if the button l5 is pressed, the station A will respond, and if each of the succeedingbuttons is likewise pressed, each of the succeedin" statio11s will correspond- 'ingly Signale y in the-same order.

eov

To understand more clearly my invention, it Will 'be advisable to follow the results accompanying the pressing of the individual buttons. It will beassumed, for the sake of simplicity, that While the buttons are beingpressed t-he armatures of the generators E and F are in such positions that the brushes and 51 are negative, and that the brushes 52 and 53 are positive; and the conductor 54 Will be known as the sleeveconductor, and conductor as the tip-conductor. When the first button 45 is pressed the sleeve-conductor 54 is, through the conductor 56a and springs 56 and 57,- placed in connection With the positive terminal 52 of the generator E, by Way of the conductor 57a. Alternating current will then flow through each of the stations A, B, C and D' from the sleeve-conductor to the grounded terminals G1, G2, G3 and G4, respectively, and back to the generator E through the ground terminal G. Each of the controlling-magnets comprises. two independent magnetic circuits-that is, the coils 58, 59, 60 and 61 each controls a magnetic circuit Which does not include the pole-pieces 18, 20, 22 and 24.

Likewise, the coils 62, 63, 64 and 65, and 66 and 67 control magnetic circuits that do not include the pole-pieces 19, 21, 23 and 25. However, the magnetic circuitsin the con trolling-magnet 14, identified with `the polepieces 18 and 19, use in common a magnetic conductor 68; likewise, magnetic circuits in- 'dividual to the pole-pieces 2O and 21 re:

spectively include also a commonmagnetic .conductor 69;'likewise the magnetic circuits through the pole-pieces22 and 23 comprise I .in .common a magnetic conductor 70; and

the magnetic circuits identified With the pole-pieces 24 and 25 also use in 4common a magnetic conductor 71. Therefore, at the first station A, when the. current passes through the condenser 6, springs 30 and 31 and the coil 62 to. ground G1, the armature 26 is attracted by the pole-piece 18, since the magneticl circuit includes the pole-piece 18 and magnetic conductor 68, unon which latter the. armature 26 is supported; said armature, aswell as the armatures 27, 28 and 29, being of magnetic material. As soon as the said armature 26 is attracted, the springs 30 and 31 are separated Vby the plunger 38 which, since thelarmature 26 is plvoted centrally at the point 72, is bound to travel directly away from the pole-piece 19. The short-circuit being removed from across the rin er 2, the-current Will then fiow through sai ringer instead-of through the springs 30 and 31 as at first. The natural result is, then, that thesignaling apparatus at this first station becomes energized, since after .the short-circuit is removed, the current can fdo nothing but iiow through the ringer 2.

At the second station, the current passes through the coil 63 to ground G2 from the 'been' described, then, it isvery sleeve-conductor 54, by Way of the condenser 8. Said coil`63 becoming energized, the armature 27 sretained in itsnormal position by the magnetic force developed at the pole-piece 20. The bell 3 is notrung because no current passes through it, since there is no difference of potential between the condenser 9 and the' ground G2; and even were there a difference of potential, then the current would pass by Way of short-circuiting springs 32 and 33, rather than through the ringer. It Will be understood, of course, that the armature 27 is pivoted centrally, the pivot being shown at 73. In the third station the current passesfrom the sleeve-conductor 54 through th condenser 10 and the coil 65, conductor 74, coil 60, springs 35 and 34 to ground G3. In this case, both the cores 22 and 23 become magnetized, but because of the air-gap between the armature 28 and pole-piece 23, the force holding said armature against ole-piece 22 is greater than the force ten ing to\ pull armature 28 from said pole-piece 22, about the pivot 75, and toward pole-piece 23. In

addition, the tension lof the spring 35 has a tendency to assist the forceat the 'polepiece 22. The armature 28 being, therefore, retained in its normal p iition, the shortcircuit across the terminals of the ringer 4, through the springs 34 and 35, is'not removed, and said ringer is, therefore, not energized. At the fourth station D the 'current passes from sleeve-conductor 54 through the condenser 12 and springs 36 and 37, through the coil 67, conductor 76, coil 61 to ground G4. Therefore, the and 25 become magnetized, ut owing t0 the air-gap between the former polepiece and armature 29 the magnetism at polepiece 25 overbalances the magnetism at p olepiece 24 in a tendencyto rotate armature A29 about pivot 77; and the armature 29 remains in its normal position. Since the springs 36 and 37 remain in contact, the short-circuit across t-he ringer 5 is not removed, and the current, instead of passing through said ringer, cuts across through said sprin swithout energizing the ringer.. From,l W' at has lain that by pressing the pus'l'i-button45 on y one station-station A-is signaled.

If the second push-button 46 is pressed, t-he terminal 51 of thegenerator F is counected with thetip-conductor 55 through the conductor 78, springs 79 and 78, and

conductor 79a. The current then, at the first statibn, passes from ground G1 through Vcoil 58 to condenser 7. magnetized, and thev armature 26 is held against thepole-piecel 19; therefore, the

springs 30 and 31 remain closed. But even were the springs 30 and 3l separated, the,

ringer 2-Would not be energized, since its terminals are not'mcludcd 1n a live arr-wit.

Said coil 58 becomes.

ole-pieces 24 i, the tipronductor 55.

armature 27' is drown by the pole-piece 21 about the pivot 73, no thut the plunger 39 seperntee the spring 33 from the spring-V32. At once the current is Switched through the ringer 3 which, ol course, will be rung. lt

is evident thet the circuit oit the current ety this station posses from ground Gr through coil 59 to ringer 3 end condenser S) to the tipconduotor 55. it the third stntion, the current pensee troni ground througl'i the short-circuiting,r Sprii'igge 34. und through coil 69, conductor lll, coil till, condenser 11 to ln this cese, also, both the cores 22 und il) become inngnetined, but the nii-gen between the pole-piece 23 anderinetnre 22 renders the niegnetic pull et the polepiece 'Weolrer tl on the pull et the pole-piece 22, nndthe ey. E55, through the E ilui'iger lll, oooh-te nur; the pull et the polepiece ne ernieture reinuine ineet fe, und i il doce noty ring. llt will be un `ed t nt the coile 60, Blnnd titi are ell t. e renie ning noticing poner. litt etntion lll the current passes from ,ground Grt through the coil lift, conductor To :nod coil titl, end 'thence through condenser 13 to the tip-conductor 55, At seid etetion, oleo, tooth sections ot the controlling'nnngnet become rnngnetized ne woe the crise nt etetlt'ion @Wing to the nir-grip between pole-pieco 2d `und armature 22, however, the pull exerted on ermeture 29 by the polopiece 25, eeeieted by the tension of the spring 37 in the seine din-iction.y overcornes the pull of the pole-piece 2d ebout the pivot 77. Naturally, since the erinnture remains inoperative, und, furthermore, eincek the terminale ot ringer 5 ere not included in any niegnetizingf circuit, the ringer et that etetion remains inactivo. ln this wey, when the button d6 io preseedgonly the ringer et etetion li ie energized, irnilnrly, When the third push-button 1'? its preseed, currentpneeee troni the ground terminarlo (all, G2, und Gt through the yurions coile toward both the sleeve and tip conductors, simultaneously. At the tiret station, half of the current posees through ground (il, the coil 58, end the` condenser 7, arriving et the tipcondu`ctor 55 whicl'i, by wey ot Ithe springe 80, 81 and 82., reaches conductor 79 and, therefore, the generator terminal 51. The other path ie from ground Gt through coil 62, 'springs 31 :1nd 30 end condenser (3 to the sleeveconductor .54h thence by wey of springe 81 end 82 to generator l?. Both ofthe coilet@ and 58 become energized, but owing to the oiivgep between polo )ieee "l5, end fermeture 2G Seid nrinetin'e 1s retained by pole-piece 19, ne 4l'iiieheen described 'in connection. with come ot the other etiitionfs- The armature 26 re1naining inactive, the shortcircnit across the bell 2 ie not moved; conoequently, seid bell ie not rung. At the second station, one path that 'the current takes extends from ground (l: through coil 63 ond the condenser 8 to the sleeve-conductor 54, and thence over yconductor 56a end through the Springe 81 sind 82 to the terminal 51 of the generetor l", The other current posses from 2zn-(mnd G2 through coil 59, short-circniting springs 33 and 32, condenser 9, tip-conductor 55, thence to conductor 78EL and to the generetor lil Again both the cores of the con trollingdneggnet 'l5 nre inegnetized. Since the megnetining forces of the coils 63 and 59 are the come, the armature 27 remains in-4 active for the reason described 1n connection- With Station A.; therefore, the bell 3 does not ring', since the short-circuit throu h the springe end 33 is not removed. t the third otetion, however, only the coil G() of f the controlling-megnet 16 becomes magnetieed, und the armature 28 is attracted by the vpole-piece 23, which letter rotates the :tornier nloout the pivot 75. The current at 'thieetntion poseenv 'from ground G3 through the rhort-circuitingl Springe 34 and 35 and coil 60 to the conductor 74. It then bronches,

holt passing through coil 64 and half 135 through coil 65; the inngnetizing etect of the coils 65 end 64 upon the core 22 is neutralized, leaving the pole-piece 23, as Was stated, to do its work. Ae,` Soon es the springel und 35 are separated by the plunger 40, the current is forced to passY through the ringer 4 on its way through coil 60, operating seid ringer. `At the station D the current cornes from ground G* through coil `6,1 to the conductor 76. Here, also, it lbranches,I into the coils 66 and 67, which are so Wound that under these conditions their nmgnetizing tendencies upon the core are neutrnlieed. Evidently, then, since only the pole-piece '25 exerts n 'pull on armature 2S),

the letter is' retained inoperative and the hell 5 remains short-circuted.

It iS evident that the current that puissesy through coil 66 reaches the tip-conductor 55 through the condenser 13, and the current passing through the coil 67 reaches the sleeve-conductor 54: by passing through the springs 37 und 36, and `through condenser 12. Obviously, then, by pressing the button 4J? the stations A, B and D are allowedto reniein silent, station C being the only one to respond. The only step remaining now is to prees the button 48, thereby placing cheV conductors 541 and 55, respectively, through the springs 86, 87, 88 and 89, inconnecton 4 Withthe terminals 52 and 51 of the4 genen eters. In this wey, the negative terminal 51 of the generator F is placedin connection with sleeve-conductor 54, and `che positive 'terminal of the generator E is placed in connection With tip-conductor 55. Under such conditions, the said generators are bridged in series across the line-conductors. At the different stations the coils are so Wound that all circuits between the ground-terminals G1, G2, G3 and G4 and the ditions the bell at the station Will not ring.

- At tht second station the current enters the 65, to retain the-armature 26 against said pole'- condenser 9 and passes through the springs 32 and 33, coils 59 and 63 to the condenser 8, and to the sleeve-conductor 54. also, both coils 59 and 63 become magnetized, and for the saine reason the bell at the station does not ring. l At the third station the current circuit may be traced from the ti conductor through the condenser 11,(:01 s 64 and 65, condenser l0 to the sleeve-conductor 54. It is evident that only the coils 64 and 65 become vma-gnetized; therefore, of the two pole-pieces 23 and 22, onl the latter becomes magnetized. It has also een pointed out that these conditions do not enable the bell 4 to ring. At the last station-station D-the circuit may be traced through `condenser 13, coils 66 and 67, through springs 37 and 36 and the condenser 12 lto the conductor 54. Pole-piece 24, Ibecoming magnetized, attracts the armature 29, rotating the latter about the pivot 7 7, and causing the plunger 41 to separate the sring 37 from s ring36.A Thus the currentt at magnetizc the coils 66 and 67, in order to continue its flow, is forced to pass through ringer-5, causing the latter to ,reduce a' sound, Of course, the currents t rown on the line-conductors 54 and 55, bythe closing o1 the push-button, very rapidly alternates in character; but it, is clear to anyone familiar with the relations of electric currents and their magnetic effects, that the results described in 4assumin the generator-,terminals 52 and 53 are positiv and terminals 56 and 51 negative, for the ima being, will be the-samedi the polarities of the said terminais' gare-'reversed .It will be understood, alsoyfor instance, 1n connection with station A, that when the coil 62 is magnetized alone,

andthe sprin s 31 and 32 separated by the armature 26 eingy attracted to said polepiece, the current that magnetized said coil 62 alsoringsthe bell 2; and notwithstanding that said current is alternating, the magnetism developed in the pole-piece 18 is able Here,

piece as long as the button 45 is pressed. Thus when the button 45 is pressed, of the 'short-circuits or shunts around each of the ringers 2, 3, 4 and 5, only the short-circuit around the ringer 2 is removed, and the current that magnetizes the core 18 and attracts the armature 26 passes cn its Way through the ringer 2, instead of across the short-circuiting loop that `includes the springs 30 and 3l. Siinilarly,when the second button 46 is pressed, only the armature of the controlling-magnet at the second station B ,is attracted, and only the ringer 3 will ring. Likewise, when button 47 1s o erated the ringer at the third station soun s an alarm, because only at that station doesthe controlling-magnet become operative to remove the short-circuit from around the ringer (rin r 4) which then receives the current tiit causes it to become active. Finally, when thefourth button 48 is pressed, the armature 29 at the fourth station D becomes attracted for reasons already described, and the current on passing from one line-conductor to the other 'asses' through the ringer 5 with the desire eiect. Clearly, then, if a line has bridged across it only one station-station A, for instance-it is possible to ring that station by pressing the proper button, button 45; Any one of lthe other stations may be retained across the line alone, and it would be possibleto ring said station by pressing` the proper'button. Also, two. stations only may be across the line, or even three. As each station Works absolutely independently of the other stations,there will be no confusion in a system operating with this arrangement, Whether all the lines carry the maximum number of stations or not. My description has been confined to one line Whose conductors are designated as 54 and 55;- but should vthere be another line proJ vided with stations similarto the ones above' 1 instance, any one of said stations could be signaled by removing the plug 49 from the. c jack 42 and inserting ity instead in the said" -ack 43, and by then pressing the proper utton.'

Fig-2 shows a modified form of the controlling-magnets, involving the saine principles that have been described in the foregoing-stations A, B, C and D, The modification in structure is the main. feature. The magnetic conductor 90 is similar to. the magnetic conductor 68y in station A, and is piv'- otally secured from its lower end to the yoke 91 that joins the coils 92 and 93. Said inem.- ler isheld in normal position against the pole-piece 94 or 95, as it may be desired,

y the tension of the spring ,96 which, in connection with spring 97, forms a short-circuiting means similar to the means embody- Ving the springs 31 and 30 in station A. 'Ihe same method of Wiring-'is carried out which has been illustrated in Fig. l. For instance-7 llie coil 92 would take the place of clic coil in station A, and the coil 92B the place of coil 62 at the saine station. lf employed at station C, for instance, tbc windings tS-Jf and 6T would be duplicated on the core inclosefl by tlic coil 92. It will be borne in mind that tlic generators should run in ysyncln'onisni, so that ilie effects described in the foregoing may be true. ltV has been tourul that good results are. obtained by baring tbe tous sa. sa, oo, occa. sa, c4, on, come c7 all of about 50() ol'nns resistance encb, Of

course, after tbc arnmtures 2G, 2T. 'and Q9 are attractedT they are then returned to tlieir normal positions`r when tne niagnetining force ceases, by tbe springs 31, 35 and Si?.

With tbe exception ol the bell at. the sub4 'scribcrs station C, all of tlie different subscribers bells or ringers are bridged across the complete metallic line-circuit comprising the parallel line-conductors and 55. it the said subscribers station C, however, tbe

'bell Il: is included in the connection to ground,

rather than in tlie bridge between tl'ie two Sides of tbc line-circuit. At the subscribers stationsA and B tlie relays have bot'n of 'their coils connected in serios with tlie bell,

and in series with tlie two condensers. so that both coils at. each station are in bridge across the talkinglcirouit. At the stations C and l), however, tbe relays each have a coil .which is not included in. the bridge, and which is simply connected lo ground. At the stat-ions ,1X-and ll, the ground connection extends from between the 'coils on the two cores of the relay, lt a centralized source of current supply is employed for furnishing tlie current for citlier talking or signaling purposes, or for bolli, suoli battery current is pre'rcnted by the condensers 6 to 13, inclusive, from flowing through tbebridges in which tbe signalreceiring means are connected It will be understood that any suit-V able, known or approved form of telephone instruments can be employed and associated with tbe dillercnt signal-receiving ineans at tlie ditlercntI subscribers stations. ln a telo phone system of this character. any suitable line and .supervisory signals, for attracting the attention ol tbe operator',v may bc ein ployed und operated in any suitable ol' ucllknown manner.' ln the dlrawiug, only enough of the operators cord-circuitis shown to illustrato tlic use l tlio saine as a part ofllic calling apparatus vtot selec* tively. operating tbc diicront. signal-recent# ingq means located-.at tl'ie diicrent subscril` ers' stations. In Atlns caso, also, it will be i'lnderstood that tbe balance of tbc switchboard operator-s apparatus niay bc 'oi any suitable or desired character. The resistanccof tlte. various coils may, of course, be *varied or adjusted to suit tlic requirements ofdiflfcrent cases. 'llie two generators, con

, grounded, und a ncctcd and arranged to simultaneously de volop impulses in tlic saine direction. are connected together in series and grounded at a point between tbcln. `Various kinds of switching' devices can. of course, be :t'or coin'iectingl tlw generalors4 with the linecircuit.

l do not limit nijvsclt to the exact construction shown and described, as itr isobrions that Various changes and niodications can be zuude therein u'itlioutdeparting from the spirit ol nn' intention.

"What l claini un my invention is l. A selective signaling system comprising a linecircuit, i plurality of signal-receiving means connected with the said circuit, and a calling apparatus for selectively operating said signal-receiving means over tbc said circuit, said calling apparatus ins cluding a couple of synchronized alternating current generators, said generators being connected ,in series and grounded at a'point between t-lieiln, and each signal-receiving means comprising an electric bell or ringer, a'nor1nally-closed shunt or short circuiting connection extending around said bell or ringer, and means for automatically opening up suoli shunt, vor short-circuiting connection Wlen die bell is to be rung.

2. A selective signaling system comprising a line-circuit, a plurality of signalueceiving means connected. with the said cir-4 cuit, and calling apparatustor selectively operating tlie said signal-receiving means over tlie said circuit, said calling apparatus includinga couple vof generators connected in series and grounded at a, point betweeny tlieni, and each signal-receiving means comprising an electric bell or ringer, a normally-closed shunt or short-circuiting con ncction extending around said bell or ringer, and nieans for automatically opening and holding open said shunt or short-circuiting connection when the bell is to be rung.

3. A. selective signaling system comprising a line-circuit, a plurality of signal-receiving means connected with the saidcircuit, each signal-receiving ineans being grounded, and a calling apparatus for selectively operating tlio said signal-receiving moans over tlic .said circuit, said calling apparatus ii'icluding a couple of generators connected in seriesnnd grounded' at a point between tlicni, and cach signal-receiving means comprising un electric bell or ringer, a normally-closed shunt. or sliort-circuiting connection extending around said lbell or. ringer, and moans for automatically opening employed t and holdin g open said shunt or short-circuiting connection when the bell is to be rung.

4. A selective signaling system; comprisceiving inc ans connected Witb the said circuit,

cach signal-receiving means being' calling apparatus normallyy disconnected from the said line-circuit, but

adapted to be connected ltherewith for the 'ed in series and grounded at a point between them, togdther with a plurality of ringmg-keys controlling the How of currentA from the generators to the line-circuit and Ycorrespondimg in number t'o the said signalreceiving means, and each signal-receiving means comprising an electric bell or ringer, a normally-closed shunt or short-circuiting connection extending' around said bell or ringer, and means for automatically,opening and holding open said shunt or short-circuiting connection i'ihenthe bell'is to be rung.

5. A seleetiiv'e signaling system comprising a. metallic line-cincuit-` a plurality of sig'- nal-receiving means bridged across the said circuit, each bridge being grounded, and a calling apparatus 'normally disconnected from the said little-circuit, but adapted to be connected thereto for the purpose of selectively operatingl said signalreceiving means, said calling apparatus including a plurality of alternating current-generators connected in series and grounded at a point between them, together with a plurality of ringing-keys whereof one is adapted for including one of said generators in series with theground and one side of the line-circuit, another for connecting the other side of the line-circuit in series With the ground and the other generator, another for connecting one of the generators in a ground-circuit including both sides of the line-circuit in parallel, and the other for connectingboth generators in series in a complete metallic circuit including both sides of the line, and each signal-receiving means comprising an electric bell or ringer, a normally-closed shunt or short-circuiting connection extending around said bell or ringer, and means for automatically opening up such shunt or short-circuiting connection When the bell is tobe rung.

6. A selective signaling system com rising a metallic line-circuit, a plurality o signal-receiving means bridged across the said line-circuit, each bridge being grounded and including a pair of condensers arranged at oppositeV sides of the signal-receiving means, and a calling apparatus for selectively operating the said signal-receiving means over the said line-circuit, said calling apparatus includinga. plurality 'of alternating currentgenerators connected in series, and each coni nected with ground, together with a plurality of selective ringing keys corresponding in number t0\the signal-'receiving means, and 'adapted for connecting up the generators in4 as many different circuits as there are sig:

nal-receiving means,`and each signal-receiving' means comprising an electric bell or ringer, a normally-closed shunt orshort-circuit, and a calling a cuiting connection extending around Said bell or ringer, and means for automatically opening up such shunt or short-circuiting connection when the bell is to be rung.

7. A selective signaling system comprising a complete metallic subscribers line, a spring-jack in which the said line terminates, a. cord circuit provided with a plug adapted l'or insertion inv said jack, a plurality of ala normally-closed shunt or short-circuitingA connection extending around isaid bell or ringer, and means for automatically opening up such shunt or short-circuiting connection When the bell is to be rung.

S. A selective signaling system comprising a complete metallic subscribers line, a plurality of signalreceiving means bridged across the said circuit, `each bridge being grounded and including a pair of condensers arranged at opposite sides of said signal-receiving means, and a calling apparatus normally disconnected from the said line, but adapted to be connected thereto for the purpose of selectively operating the said signalreceiving means over the said line., said calling-apparatus including a plurality of alterelectric bell'or ringer, a normally-closed shunt or short-circuiting connection extending around said bell 'or ringer, and means for automatically opening up such shunt or short-circuiting connection when the bell is to be rung. l

9. A selective signaling system comprisinga line-circuit, a plurality of .signal-receiving means connected with the said cirl lparatus for selectively operating sald signa -receiving means over the said circuit, said calling apparatus including a couple of synchronized. alternatingpurrent generators,.said generators bemg connected 1n series and grounded at a point between them, at least oneof said. signal-receiving means comprising an electricI bell or ringer, a wnormally-closed shunt or short-circuitingr connection extending around said bell or ringer, and means for` automatically opening` up such shunt or short-circuiting connection when the bell is to be rung.,

l0. A selective signaling system comprising a line-circuit, a plurality of signal-receiving means connected with the said circuit, and calling apparatus for selectively operating the said signal-receiving iilcans over the saidcircuit, said calling apparatus including a couple of generators connected in series and grounded at a point between them, at least one of said signal-receiving means comprising` an electric bell or ringer, a norn'ially-closcd shunt or short-circuiting connection extending around said bell or ringer, and means for automatically opening and holding open said shunt or shortcircuiting connection when the bell is to be rung. 1

11. A selective signaling system comprising a line-circuit,l a plurality of signal-rcceiving means connected With the said circuit, each signal-receiving` means being grounded, and acalling apparatus for selectively operatingl the said signal-receiving means `eter the said circuit, said ailing apparatus including' 'a couple of generators connected in series and grounded at a point between them, at least one of said signal-receiving means comprising an electric hell or ringer, a normally-closed shunt or shortcircuiting connection extending around said Y bell or ringer, and means for automatically 35V openingl and holding open said shunt or short-circuiting connection when the bell: is to be rung.

12. VA selective signaling system comprising line-circuit, a plurality of signal-receiving means connected with the said circuit, each signal'- receiving means being grounded, and a calling apparatus 'normally disconnected from the said line-circuit, but adapted4 to be connected therewith for the purpose of selectively operating the said sin:il-receiving means, said calling'- apparatus-includinglga pluralityof generators connectd ini'seies and grounded at a point between them, together With a. plurality of ringingkeys controlling' the -tlow of current from the generators to the line-circuit and corresponding in numbervto the said signalrece-iving means, at least one of said signal- 4receiving means comprising an electric bell 0r ringer, a normally-closed shunt or shortcircuiting connection extending varound said hell or ringer, and means for automatically opening and holding open said shunt or short-,circuiting connectionV When the bell is to he rung. i'

13. A lselective signaling system comprising-- a metallic linecircuit,5 a plurality of signal-receiving means bridged across the anda calling apparatus normally disconnected from the said line-circuit, but adapted to be connected thereto for the purpose of selectively operating said signal-receiving means, said calling apparatus including a .plurality of alternating current-generators another tor connecting the other side of the` line-circuit in. series with the ground and the other generator, another for connecting one of the generators in a ground-circuit. including both sides of the line-circuit in parallel, and the other for connecting both generators in series in a complete metallic circuit including hoth sides of the line, at least one of said signal-receiving means comprising an electric: bell or ringer, a normallyclosed shunt or short-circuiting connection extending .around said bell or ringer, and means for mitomatically opening up such shunt or short-circuiting connection when the hell is to he rung.

14. A, selective signaling' system comprising a metallic line-circuit', a plurality of signal-receiving means bridged across the said line-circuit, each bridge being grounded and including a pair of condcusers arranged at opposite sides of the signalreceiving means, and a callingappi'iaratus for lselectively operating the said signal-receiving means over the said line-circuit, said calling apparatus including a plurality of alternating currentgenerators connected :in series, a-nd'each connected with ground, together with a plurality of selective ringing-keys corresponding in number to the signal-receiving means, and adapted for connecting up the generators in as many dillerent circuits as there are signal-receiving means, at least one of saidsignal-reaching means comprising an electric bell or lringer, anormally-closed shunt or short-circuiting connection extending around said bell or ringer, and means for automaticallyopening up such shunt or short-circuiting connection when the bell is to be rung.

15. A selective signaling system comprising a complete metallic subscribers line, a spring-jack in which the said line terminates` `a'cord circuit provided with a plug adapted for insertion in said jack, a plurality of alternating' current-generators connected in series `and grounded at, a point between them, a plurality ot' leeys for variously connecting the generators Vnfith either one or both .sides of the cord-circuit, and a plurality of signal-receiving nlcans'bridg'ed across the said line. each bridge being grounded,

and cach signal-receiving means being adapted to be operated. by its allotted key and no other, at least one of said'l signal-rcceiying means-comprising an electric bell or ringer, a normally-closed shunt or short-ciracross the said circuit, each bridge being grounded and including a pair of condensers arranged at opposite sides of said signal-receiving means, and a calling apparatus normally disconnected from 4the said line, but adapted to be connected thereto for the purpose of selectively operating the said signal-receiving mea-ns over the said line, said calling apparatus including a plurality of alternating current-generators, together with switching devices adapted for vari.- ously connecting one or more of said generators with either' one or both sides of the line-circuit, and whereby said generators may be connected up in as many different circuits as there are signal-receiving means, each signal-receiving means heilig responsive only when its allotted line-circuit closed, at leastone of said signal-receiving means comprising an electric bell or ringer, a normally closed shunt or short-circuiting connection extending around said bell or ringer', and means for automatically opening up such shunt or short-circuiting connection when the. bell is to be rung.

"17. A selective signaling system comprising a line-circuit, a plurality of signal-receiving means connected withthe said circuit, and a calling apparatus for selectively operating said signal-receii-ing vmeans over the said circuit, said calling apparatus including a. couple of synchronized alternating current generators, said generators being connected in series and grounded at a point betweenv them, and each signal-receiving means comprising an electric bell or ringer, a normally-closed shunt or short-circuiting connection extending around such. 'bell or ringer, and .a relay having one or more windings connected in series with said bell1 y Vsaid relay being adapted to (apen the said shunt or short-circuiting connection when it,

is desired to ring the bell.

18. A selective .signaling system comprisl in a' line-circuitl a lura-l-iff of sional-rcceiving means connected with the said cir- ."55

cuit, and calling apparatus for selectively operating the said signal-receiving means over the said circuit, said calling apparatus 'including a couple of generators connected in series and grounded at. a point between them,land each signal-receiving means comprisingan electric bell or ringer, a normallyclosed shunt or shortcircuit-ing connection extending around such bell or ringer, and a relay ,having one or'more windings connected'4 in Series with said bell, said relay shunt or short-circu'iting connection when itl is desired to ring the bell.

19. A selective signaling system comprising a line-circuit, a vl'ilurality of signal-receiving means connected with the said circuit, each signal-receiving means being grounded, and a calling apparatus for selectively operating the said signal-receiring means oi'er the said circuit, said calling apparatus including -a coupler, of generators connected in series and grounded at a point between them, and l each sigmil-receiving meansI comprising an electric bell or ringer, a normally-closed shunt or short-circuiting connection extending around such bell 01 ringer, and a relay having one or more windings connected in series with said bell, said relay being adapted to open and hold ope-n said shunt or short-circuiting connection when it is desired to ring the bell.

20. A selective signaling system comprising a line-circuit, a plurality of signal-receiving means comiected with the said circuit, each siglati-receiving means being lwindings connected in series with said bell,

said relay being adapted to open and hold open said shunt or short-circuiting connection when it is desired lo ring the bell.

21. A selective signalii'igsystem comprising a nletallic line-circuit, a plurality of signal-receiving means bridged across the said circuit, each bridge being grounded, and a calling apparatus lnormally disconnected from the said line-circuit, but adapted to be connected thereto fo i the purpose ot' selectively operating saidsigna-l-receiring means, said calling apparatus including a plurality oli alternating curient-generators connected in series and grounded at a point between them, together with a plurality of ringingkeys whereof one is adapted for including one of Said generators in series with the. ground and one side ot' the line-circuit, another for connecting the other side of the line-circuit in series with the ground and the other generator', another` for connecting one 'of the generators in agroulul-circuit including-both sides of the line-circuit in pargrounded, and a falling apparatus normally esencia allel, and. the other for connecting both generators in sei-ics in uV conipletc metallic cir cuit.' including bothvsides of' the line, and eachlsignal-rccciving means comprising an electric b ell or ringer, a 1tornially-closed shunt for short-circuiting connection exH tending around such bell or rin er, and a relay having one or more windings connected in series With said bell, seid. relay being udaptedio open the said shunt or short circuiting` connection when it .is desired t ring the bell.

22. A selective signaling system comprising a metallic line-circuit, a plurality ot signal-receiving means bridged across the said line-circuit, each bridge being,r grounded and inclx a pair ot condensers arranged at ,oppy sides of vthe signahreceiving ineens, and a calling apl'niratus for selectively operating the said sigg-nulfrcceiving` means over the said line-circuit`r said calling apparatus including,` i iiilurality ol; elternating eurrentgeneratorsv connected in l series, and each connected with ground, to-` gether With'a plurulity'ot sel .ct-ive ringinglreys corresponding in number Vto the signet receiving means, and adapted 'for connecting up thelgenerators in as many diliierent circuits as; there are signalieceiving means, and each signtil-receiving` .means ceuipriiunur an electric bell vor ringer, a normallyeclosed shunt orshortcircuiting connection extending aroundsuclrbcll or ringer, and relay having one or more windings connected in serieswith said bell, said relay being' adepted to open the `seid shunt 'or sliort-circuit ing connection when it is desi:Y il to ring` the bell..

' 23, A selective signaling system comprising a complete metallic subscribers line, a

spring-jack in which .the said line ternunected' in seriesand grounded at a puin be f tween them, alplnrality of l( s for variously `connecting the generators u ith either one orbotli sides of the' cord-circuit, and 'a plurality of' signal-ieceiving` ineens bridged across the said line, euch bridge being grounded, and cach signahreceiving means being adapted to be operated by its allotted key and no other, and each signatreceiving means comprising an electric hell. or ringer,

a'iiormally-closed shunt or sliiort-cireuitingA 4connection extending around such bell orv ringer,4 and a relay leaving` one or more vwindings connected in series with said bell,`

said relay being Vadapted to open the seid shunt orshort-circuiting connection when it is desired to ring the bell.

24. A selective signaling system compris ing a complete" metallic subscribers line, a

'Y plurality of signalieceiving means bridged across the said circuit. each bridgeheing,

grounded and including aliair of condensers arranged at opposite sides of Said signal-receiving means, and. a calling apparatus nor ina-'I ly disconnected from the-said line, but adapted to be connected thereto for the purpose .oit selectively operating the said sigh nal-receiying means over the said line, said calling apparatus including` a plurality of Y alternziting;` current-generators, together with switching devices adapted for-variously connecting4 one or .more of said' generators with either one or both sides of the lineycircuit, and whereby said generators may be "ed, to open the seid shunt or sliort-circuiting connection when it is desired to ring=\1'tlie bell.

25. A selective signaling system comprising a line-circuit, a. plurality of signalieceiving ineens connected with tlie'said circuit, and a calling apparatus for selectively operating seid signalieceiving ineens over the seid circuit, said calling apparatus including,- a couple of synchronized alternati ing current generators, said generators being,` connected in series .ant grounded at a point between theni, at leasty one of said sig; nul-ri- Ceiifing ineens comprising an electric bell or ringer, -a noinially-closed shunt or short-circuiting coiniection extending around such bell or ringer, und a relay having one or more windings connected in series with said bell, said relay being` adapted to open the said shunt or short-circuiting connection when it is desired to ring" the hell.

QG. A selective signalingsystein compris' ing a line-cir'. iit, a gluriility o signal-.ie reiving inezxns connected With the said cir cuit, and calling apparatus for selectively operating the seid signal-receiving means over 'the said circuit, said calling' apparatus including a couple of generators connected in' series und grounded at a point between there, at least one ot said signalueeeiving means comprising un electric bell or ringer, a norinallyclosed shunt or shortffcircuiting connection extending around such bell or ringer, and a relay having' one 4or more windings connected in series with said bell, said relay being adapted to open and hold open said shunt or short-cireuiting connectionY when t is desired to ring the bell.

iet

iis

2,7. ,A' selective signaling system comprising,V a line-circuit, a plurality of signalfrey eeiving means connected with thexsaid cirf. cuit, each signal-receiving 'means being grounded, and a calling apparatus :torseler` tively operating vthe said signal-receiving means over the said circuit, said calling apparatus including a couple of generators connected in series and grounded atv a point between'thciu, at least one ot' said Signat receiving .means eoi'nprising an electric bell or ringer, a norn1aflly-closed shunt or sher oircuiting connection extending around sueh 'bell or ringer, and a relay having one. or more windings connected in series with said bell, said relay being adapted to open and hold open said shuntwor short-eircuiting cennection When it is desired to ring the bell.

28. A selective signaling system Comprisw ing a line-eirouit, a plurality et signal-receiving means connected with the said oirouit, each si 'nal receiving n'ieans being grounded, and a calling apparatus nornnilly disconnectei'sl.l frein the said line-oireuit., but adapted to be connected tlfierewi'tii for 'the purpose ot selectively open-ating the said signal-receiving ineens, said calling appa.- ratus including a plurality of generators connected A'in series and g' ounded at a point between them, together with a plurality of ringing-keys controlling the lionT ot current from the generators to the line-circuit and corresponding in nombra i the said signal receiving rneans, at lea aid signalreceiving means eoinplieingduielectric bell or ringer, a nori'na-lly'fnluse'd 'shunt or shortoirouiting connection ,extending around suoli bell or ringer, and ti relay having one or more windings connected in series with said bell, said relay bei g adapted to open and hold open said shu fit or sliort-eirouiting connection Whe-n it is esired 'to ring the bell.

A29. A. selective signaling system comprisn ing a metallic line-circuit., a plurality of signal-receiving nie/ans bridgedv across `the said circuit, each bnidge being grounded, and a calling apparatus normally disconnected from the said/line-cireuit, but adapted to be connected thereto .for the purpose of seleo tively operating said signal-receiving means, said calling apparatus including a. plurality of alternating current-generators connected inseries and grounded at a point between them, .together with a plurality of ringing-keys whereof one is adapted for including one of said generators in series With -the ground and one side of the line-circuit, another fogconne'cting the other side of the ,line-circuit in series With the ground' and the. other generator, another for connecting one ofl the generators in a groiindcireuit including both sides of the line-circuit in parlel, and the other for connecting both genirators in series in a complete metallic oir* cuit includil'lg both sides of the line, at least one ofsaid' signal-.receiving means coniprising an electric bell or ringer, a normallyclosed shunt -or short-circuiting connection extending around such bell or ringer, and a relay having one or rigore' liiiiitlingsconnectenligne ed in series with said bell, said relay being adapted to open the Said shunt or short- Limuiting connection vwhen it is desired to .ring the bell.

30. A selective signaling system comprising a metallic line-circuit, a plurality of signal-receiving ineens bridged across the said line-cireuit, eaeli bridge being grounded and inelzffding a pair of condensers arranged a' opposite sides of the signal-receiving means, and a calling apparatus for selectively operating the said signal-reeeiving nieane over the said luie-circuit, said calling apparatus including a plurality of alternating ourrentgenerators connected iny series, and each con-- neetcd with ground, together iaith a plu* rality of entire ringinglneys corresponding in niu'nber to the signal-receiving means, and adapted for connecting up the generators in many ditlerent circuits as time signal-receiving means, at least one at said signal-receiving ineens eo'niprising an electric bell or ringer, a norn'ially Closed slnnit or short-eireuiting connectioii extending around. suoli bell or ringer, and a ,relay lievii'ig one or more windings connected in series With said bell, said relay being adapted to opentlie said 'shunt or shortyrireuiting connection when it is desired to ring the bell.

.Sli A selective signaling system eonipris-l ing a complete metallic sul ribers line, a spring-jack in Wliieh thesaid line tern'iinates, a cord-circuit provided with a plug adapted for insertion in said jack, a pluot' alternating .zurrent-gencraters eonnected in and grounded at a point between them, a plurality ot keys tor variously connecting the generators with either one or both sides of the cord-circuit. and a plurality of signal-receiving means bridged across the said line|` each bridge being grmnuled, and each sign:il-receiving means being adapted to be operated by its 'alhitted lcey and no other, at least one oi said signalreeeiving ineens comprising an electric bell or ringer, a normally-elosed shunt or shortcireuiting connection exten ding around such bell or ringer, `and a relay having one or more windings connected in. series with said bell, said relay being adapted to open the said shunt or short-circuiting connection when it is desired to' ring' the bell'.

32. A selective signaling system compris ing a Complete metallic subscribers line, a plurality of signal-receiving means bridged across the said circuit, -each bridge being i grounded and including a pair of eondenscrs adapted to heconnected thereto for the purpose of selectively operating the said signal# 'receiving means over the said line, said calling apparatus .including a, plurality of alter nating v'current-generators, together with switching devices adapted for variously con- I neeting one or more of said generators Withwhen its allotted line-circuit is' closed,pat' least lone of said signal-riesciving;ineensV comprising-ancienne bell or ringer, a nor-f nial y-closed shunt or shoi'fticircuiting connection extending around suclr, bell or ringer, and faK relay having one or more' windings connected in series with said bell, said rela-y being adapted toopen the vsaid shunt onshort-fcircuiting connection when it is desired to ring the` bell. 4

A selective signalii'ig system comprising a line-circuit, a liilnrality-'oi signal-rcceiving means connected with the said circuit, and a calling apparatus for selectively operating said Sigrid-receiving'means over the saidcircuit, said calling apparatus includinga couple of synchronizedalternating current generators, said geneators being connected in series and -grmn'nlcd at a point between them, and cach of said signalreceiving means comprising an electric bell or ringer,.a normally-closed shunt or shortncircuiting connection extending around such bell or ringer, and a relaY adapted for opening the said shunt or slnn't-circuiling connection when the bell is to be rung, said'relay lzaaving a plurality of coils each of Which- 1s in series with the' bell or riliger.

34.. A selective signaling system comprising a line-circuit,'a plurality ot' signal-re'- ceiving means connected with the said circuit, and calling apparatusy for selectivelyl operating the' said signal-receiving ineans over the. said circuit, said calling apparatus including a. couplenot gene 1ators connected in series and grounded at 4a point between them, and each ot v. said sig-nal-receiving means cornln'isinglanelectric bell a nornlally-closml shunt or short-circniling cuit,

connection extending' around suclibell or ringer, and a relayr adapted for opening and lioldi; h* open said shnntor short-circuitinir connection when .'lie bell is to be rung, said relay having; a plurality bf coils each of which isinserieswilh the. bell or'ringer.

l selective signaling system con'iprisingv a line-circaiil, a plurality` ot signal-receiving n ieans connected with the said cile'- 'eaeli signal-recelving` means "beinegroiilndedg"an'd aV calling appara(usgox selectively. operatingr the said sign:1l-receiving means over the said-circnit, said call-ing apparatus-including. a' couple of gei'wral'ors connected in series and grounded at a' point 'between thennand eac-lr of lsaid signal-receiv'ing' means com prising an elect-ric bell or ringer, avnorinally-closed shunt or short-ciror ringer,

cuitinig,r connection extending around such bell or ringer, and a relay adapted for open- 'ing and holding open saidshunt or shorteach of which. 1s in series with the bell or ringer. y l Y A selective signahngsystein comprising a line-cireuitfa plurality of signal-receiving means connected Wit-l1 the said cir- 75 cuit, each signal-receiving means being grounded, and a' calling apparatnsnormally disconnected from the said line-circuit,` but `adapted to be connected therewith for the purpose ot selectively operating the said signal-receiving means, said calling apparatus including a plurality of generators connected in series and grounded' at a point between them, together with a plurality of ringiiig-lreys controlling the flow of current i'roin the generators to the line-circuit and correspmidini;r in number to the said signalreceiving means, and each of said Signal receiving .nic-ans comprising uan electric bell or ringer, a normally-closed shunt or shortcirci-iiting connection extending around suoli bell or ringer, and a relay adapted for opening-and holding` open'said shunt or shortcircuiting connection when the bell is to be rung, said relay having a plurality of coils 9 5 each of which in series with the bell or ringer. l" .Y

37. A selective signaling system comprising' a metallic line-circuit, a plurality of signal-receiving means' bridged'aeross the 100 said circuit, eachvbridge beinggrounded, and a 'eallii'ne apparatus normally Vdisconnected from the said line-circuit, but adapted to be connected thereto for the purpose of 1selectively operating' said signal-receiving 105 means, said calling apparatus including. a plurality ot' alternating current-generators connected in series and grounded ata point between them, together witli'a plurality ofringing-keys whereof one .is adapted-for including one'of said generators in seriesivith the' ground and one side of thev line-ircuit, another for connecting the other side of the line-circuit in series with' `the ground4 and ,A the other generator, another for connecting 115, one of the generators in -a ground-circuit including bothv sides of the line-circuit in parallel, and the other for coi'inectingw both generators inseriesI in a ycomplete metallic circuit including' both sides oiE the line-,and 120 each ol." said signal-recelving means coin-` prising an clekiftric bell or ringer, a i'lorn'iallyclosed shunt or sllort-c-ircniting connection extending aroundV such bell or ringer, and a 'relay adapted 'for opening the said shunt'or 3:2? short-circuitiun connection when the 'bell is to berlino, said relay having a plurality of!"`4 coils each of which 'is in series Withthe'bell or ringer. Y i 'i 38.'A selective vsignaling system comprising a metallic line-circuit, a plurality of signal-receiving means bridged across the said lim-ecircuit, each bridge being grounded and including` a pair of condensers arranged at opposite sides of the signal-receiving means, and a calling apparatusfor selectively operating the said signal-1eceiving means over lthe said line-circuit, said calling apparatus including a plurality of alternating -cln'rent-generators vconnected in series, and each connected with ground, together with a plurality of selective ringing-keys corresponding in number Vto the signalre .ceiving means, and adapted for connecting up the generators in as many different circuits as there are signal-receiving means, and each of said signz'll-receiving means conv prising an electric bell or ringer, a normallyclosed shunt or short-circuiting connection extending around such bell or ringer, and a .relay adapted for opening the said shunt or short-circuiting connection when the belll -is to be rung, said relay having a plurality ralityf' alternating `current generators connected in series and grounded at a point between them, a plurality of keys for rariously connecting the generators with either one 1 bot-h sides of the cord-circuit, and a plurality ot signal-receiving means bridged across the said line, each bridge being grounded, and each signal-receiving means being adapted to be operated by its allotted key and no other, and each of said signal-- receiving means comprising an electric bell or ringer, a normally'closed slnmt'orvshorteircuiting connect-ion extending aroundbsgch bell or ringer, and a. relay adapted for open-4J ing the said shunt or short-circuiting con-A nection when the bell is'to be rung, said relay having a plurality of coils, each of which is in series with the bell or ringer.

40. A selective-signaling system comprising a complete metallic subscribers line, a plurality of signal-receiving means bridged across the said circuit, each bridge being 'grounded' and including a' pair of condensers arranged at opposite sides of saidsignali'eceiving mea-ns, and a calling apparatus normally disconnected from the said line, hutadapte'l vto connected thereto for the purpose of selectively operating the said signal-receiving means over the said lineY1 said calling apparatus including a plurality of alternating current-generators, together with switching devices adapted for variously connecting oneor' more of Asaid generators with either` one or both sides ot' the line-.'circuit, and whereby said generators may be connected up in as many different circuits asthere are signal-receiving means, each .signal-receiving means bei n g responsive only when its allotted line-circuit is closed,

comprising an electric bell or ringer, a nor mally-closed shunt or short-circuiting con nection extending around such bell or ringer, and a relay adapted for opening the said the bell is to be rung, said relay having a plurality of coils each of which is in series lwith the bell or ringer.

al. A selective signaling system comprisceiving means connected With'the said circuit, and a calling apparatus for selectively operating said signal-receiving means over the said circuit, said calling apparatus incurrent generators, qsaid generators being connected in series and grounded at a point between them, at least one of said signal-re ceiving means comprising an electric bell or cuiting connection extending around such bell or ringer, and a relay adapted for opening the said shunt or short-circuiting con; nection when the bell is to be rung, said reis in series with the bell or ringer.

l2 A selective signaling system com rising a line-circuit, aplurality of signa -receiving means connected with the said ciroperating the said signalreceiving means over the said circuit,'said calling apparatus including a couple of generators connected in series and grounded at a point between melius comprising an electric bell or ringer, a normally-closed shunt or short-circuiting connection extending around such bell or fn/ger, and a relay adapted for opening and connection whenthe bell is to be rung, said relayhaving a plurality of coils each of .which is in series withthe bell orringer. l 43. A selective signaling system comprising a line-circuit, a pluralit ceiving means connected Witi the said circuit, each signalreceiving means beingl grounded, and a calling apparatus for separatus including a couple of geln-n-ators connected in series and grounded at a point bctween them, at least one of said slgiiahrcceiving means comprising an electric bell or circuiting connection extending around such bell or ringer, and a lrelay adapted for open ing and holding open said shunt or shortcircuiting connection when the bell is to -be and each of said signal-receiving means shunt or shortrcircuiting connection when 75 ing 'a line-circuit, a plurality of signal-re 80 cluding a couple of synchronized alternating ringer, a normally-closed shunt or short-cirlay having a plurality of coils each of which cuit, and calling apparatus for selectively them, at least one of said signal-receiving 105 holding open said shunt or short-circuiting of signal-reectively operating lthe saidsignal-receiving means' over the said circuit, said calling ap- 120 ringer, a normally-closed shunt or short 125 rung, said relay having 'af plurality ofcoils 130- each ofV which is ringer.- i i 44'. vA selective signaling eysten'i compris'- ing a `line-circuit, a plurality of-signal-re in series With the hell lor ,ceving'means connected with the eaidcircuit., each signalreceiving .means being` groundedgand acallin ,y ap iaratus normally r disconnected from the saidlliiiefcircuit, but adapted toA be connected therewith'- for the 1o purposeot" selectively operating the said eig-v iial'a'eceiving means, 'said calling apparatus including aplurality of generators connected in series and-'grounded `at a point'hetween thein together with a plurality of ringing keys controlling the flow otcurient from the y i generators kto the 'line circuit nand corresponrlinigify in number to the e'aid S1g1fial-recciviiignieans, at least'one ot said signal-re ceiving'ineane comprising an electric hell or ringer, a normally-closed shunt .or short circuitin'g connection extending` around Stich hell or ringer, and a relay adapted for opening and holding openeaicl shunt or ehcrt,a

n circuiting connection when the` hell is to hey rung, said relay hairline;v a plurality of coils reaclifof Which is in series With the hell or ringer. j

p p :5. A selective signaling syetein comprising a metallic line-circuit, a plurality of sig-- n'alfijteceiving means bridged across the eaid circuit, each bridge beinggrounded, and a 'calling apparatus normally disconnected troni the eaid lineecircuit, but adapted to loe connected thereto'ftor the purpose ot selec l tivcly'operat-ing sind e'ginal-recei'viiron ineens,

said' calling apparatus including a plurality oiialternatingcurrent-generators connected in series and grounded 'at a point between' them,4

together with a plurality of ringing-keys 40 whereof one is adapted for including; one o s'aid generators in series 'with the ground and one side ofthe .line-circuit, another ior, connectingtlie other side 'ofthe line-circuit in feeiies with the ground and the other ,genera-v lrtoij, another for connectiii'gi1 one olf the generators in a Atri-ound-circuit includinpjhctli Sideeof the line-circuit 1n parallel, and the Gtherfor coi'inecting hotli generatore in se? ricain a complete metallic circuit including '5 0 botheidee .of the line, at Ione ol:- eaid eignalreceiving means comprising an electric hell or ringer, a normallycloeerl nh unt or el1orti ci'icuiting connection 'eatending1 arounil such hell orringer, and a relay adapted for opcn-v ing thelsaid-ehunt or Shortcircuiting connection when the lhell is to he run eaiclrelay having; a plurality ot coils' each ot' which is in series with the bell' or ringer. I

46. A selective signaling' sys-teni conip'rie- '60 infr a metallic line-circuit, a plurality of ein;-

. nal-receiving: means; bridged across the eaitl linefcircuit, each. bridge .being yiii-ouin pled la n d including a pair of condei'xsere arranged at: opposite sides 55: lanti a calling lapparatus for selectively open of the Signal-receiving ineens,

carece ating the said signal-receiving means over the said line-circuit, said calling apparatus including a plurality of alternating current,-

i generators connected in series, and each coii-` nectecl Withf ground, together with a plu rality Vofy selective ringingdeye correspond vingin number to the eignalgreceiving means, and adapted for connecting up the genera,-

huiit or short-circuiting connection extend ing around Such hell or ringer, anda relay adapted for-opening the said shunt or short circuiting connection when the bell.- is to be rung, said relay having a plurality ot coils each of which is in useries with the bell, j

4:7. A eelectiye signaling e-yeteni coinprieing 'a complete metallic euhscriloers l1ne,'.a springvjack in whichv the eaid line terminates, a cord-circuit pi'oyidcfl with a plug),` adapted Vfor insertion in `lsaid jaclr, a 'plir ralityfol alternating current-generators connected in serieaand grounded at pointhe tween'. them, a plurality'otI keys for yuriA ouelyv 'connectingl the generators with either one or both sides oi the cord-circuit, and a plurality of signalreceiving means bridged across the said line, each` bridge heine; grounded, and each signal-receiving means heini; adapted to loe op@ .ated by itsallottecl key and no other, at least one of Saidy ein-nalreceiving' nieane comprising' lan electric hell or ringer, a normally-closed shunt or short circuiting e'zonnection extending around Such hell o r ringer, and a rela-y adapted for opening the Said ehunt or shorty-circuitingl con- .ne-ction when the hell ie to he rung, said rclay having a plurality'of coile each of which is in series with the hell oi" ringer. y

48. A selective Signaling; system compris;n ino' a complete metallic Sulieerihee line, a plurality 'ot eignalreceiving means; hrulncil across the .Said circuit, each bridgeubeing grounded and including a pair of condcnecre arranged at oppoeite sides of said signal! receiyiinel ineane, and a calling apparatus-r normally disconnected from the Said line, hutv adapted to he connected 'thereto 'for the purpose of selectively operating the; `said .Signal-receivingy ineane over the said line, said calling' apparatus including a plurality ot alternating current-generators, together with Switching devices adapted for vari'- ouely connecting one or more of said`genoratore with either one or liothr sidee oftheV lincfcircuit, and Wherehy said generators may he coi'inccted up in as many ditferent circuits as there-are Signal-receivingineens, cach Signal-receiving nicans being respon eivc only when ite allotted line-circuit` ie closed, at least one of Said signala'eceiuingr means comprising an electric hell or ringer,

ESO

a normally-closed shunt or short-circuiting connection extending around such bell or ringer, and a relay adapted for opening the said shunt or short-circuiting connection when the bell is to be rung, said relay having a plurality of coils each oit Which is in series with the bell or ringer.

49. A selective signaling system comprising a line-circuit, a plurality of signal-receiving means connected with the said circuit, and a calling apparatus for selectively operating said signal-reeeiringl means over the said circuit, said calling' apparatus including a couple ot synchronized alternating current generators, said generators being connected in series and grounded ata point between them, and each signal-ieceiring inea-ns comprising a. normally and locally short-circuited electric bell or ringer. y

50. A selective signaling system comprising a line-circuit, a plurality of signal-receiving means connected with the said circuit, and calling apparatus for selectively operating the said signal-receiving means over the said circuit, said calling apparatusy including a couple oi2 generators connected in. series and grounded at a point between them, and each signal-receiving means com-i prising a normally and locally short-circuited electric bell or ringer, together with automatic means for holding the short-circuit open during operation of the ringer.

5l. A selective signaling system comprising ay line-circuit, a plurality of signal-receiving means connected With the said circuit, each signal-receiving means being grounded, andl a, calling apparatus for se lcctirely operating the said signal-receiving means over the said circuit, said calling apparatus including a couple of generators connected in series and grounded at a point between them, and each signal-receiving means comprising a normally and locally slioit-circuitcd electric bell or ringer, together with automatic means Ifor holding the shortcircuit open' during operation ot' the ringer. 52. A selective signaling system comprising a line-circuit, aplurality o" signal-receiving means connected with the said circuit, each signal-receiving means 'being grounded, and a calling apparatus normally disconnected from the said line-circuit, but adapted to be connected l'therewith for the purpose oi selectively operating the said sigiialicceiving means, said calling apparatus `including a plurality ol" generators connected iu series and grounded at a point between them, together with a ringing-keys controlling the itlow ol t rent from. the generators to' -tli'e line-circuit and corresponding in numbertn the said signal* receiving means, and each signalsreceiving means comprising a normally-and locally slioit-circuited electric bell or ringen tgether with automatic means for holding ing apparatus normally dis` plurality of' eeeacs the shortfcircuit open during` operation of the ringer. ,y

53. A selective signaling s y/ tiem comprising a metallic line-circuit, a pluiality of signal: receiving means bridged acre., `the said cir* cuit, each bridge being grounl and a callnected from to beconitil selectively.

the said line-circuit, but ada` uected thereto 'for the purpo operating said signalfreceix l lneans, said calling apparatusincluding@ plurality of alternating current-generators fconnected in series and grounded at a point between them, together with a plurality @Ringing-keys whereof one is adapted for including one of said genentors in series with the ground and one side oit the line-circuit, another for. connecting the other side of the line-circuit in series with. the ground and the other generator, another for connecting one of the generators in a ground-circuit including both sides of the line-circuit in parallel, and the other for connecting both generators in series in a completo metallic circuit including both sides ol the line, andeach signal-receiving means comprising a, normally and locally short-circiilited ringer.

5l. selective signaling system comprising a metallic line-circuit, a plurality of signal-receiving means bridged across the said line-circuit, each bridge being grounded and including a pair of condensers arranged at opposite sides ot the signal-receiving means, and a calling apparatus for selectively operating the said signal-receiving means over, the said line-circuit, said calling apparatus electric bell or p including a plurality of alternating current-ar generators connected in series, and each connected With ground, together with a plu-- rality ot selective ringingkeys correspond4 ing in number to the signalereceiving means, and adapted for connecting up the genera- .tors in as many different circuits as there are signal-receiving means, and each signalreceiving means comprising a normally and locally shorbcircuited electric bell or ringer.

55. A selective signaling system compris ing a complete metallic subscribers line, a spring-jack in which the said line terminates, a cordcircuit provided. Wit-h a plug adapted for insertion in said jack, a plurality of alternating eurent-generators connected in series and grounded at a point betu'cen `the Y a plurality olteys for Vari-V ously connecting the generators with either one or both sides of the cord-circuit, and a giilurality ot signal-receiving means bridged across the said line. each bridge being grounded, and each signal.receiving means being adapted to be operated by its allotted key and no other, and each signalsreceiving means comprising ay normally and locally short-circuited electric bell or ringer.

56., A selective signaling system compris lSO ing a complete metallic subecrib'ers line, a.

plurality of signal-receiving means bridged vacross the said circuit, each bridge being grounded. and includingr a pair ot' condensers 'arranged' at opposite sides of said signal-receiving means, and a callingapparatus normally disconnected from the saidline', but adapted to be connected `thereto for the purpose of selectively operatingr the Said eignal-receiving means over the said line, Said calling apparatus including aplurality ot alternating currentgenerators, together, with switching devices adapted for variously connecting one or more of Said generators with oither one or botheides ofthe line-circuit,l

ing a line-circuit", a plurality ot' signabrc ceiving inea-ns connected with the said cir c'li1t,and a calling apparatus :tor selectively operating Said eignal1eceiving means over -the said circuit, 5said calling apparatusinclnding a ,couple of synchronized alternating current generators, said generators bef ing connected in' series and grounded at a point between t-hein, at lea'st one of said aignalreceiving nieanscoinprising a. normally and locally 'short circuited .electric bell or ringer.

5S. Y LX selective signaling systenreomprisingr a line-circuit, a plurality ot vsignal-receiving means Connected with the said cir enit. and calling apparatus for eeleetively operating the Said signabrec'eiring means over the said circuit; .saidcalling apparatusA including' a couple of generators connected in series and grounded at a point between them, at least' one o't' said signal-receiving .im-.ans` comprising a normally and locally Short-eircuitedI electric hell or ringer', to-

g'otlier with automatic means for holding the short-circuit open during operation ot the ringer. 'i

59. A selective signa-ling system, conipriev ing a. line-circuit., al plurality of signal-'receiving` means c'onnec'ted with the eaid'cir cuit,4 each signal-receiying mennebeing grounded, and a 4calling apparatnsor selec; tively operating the said signabreceivii-ig ni'eans over the saidl circuit, said calling ap isti.

'paratus, including a cimple'of gein-ratiur:-v

connected in series and grounded at a point between them. atleast one of said signal-re- Vceivinigpmeans .comprising a noi-mall)r and lo fallyshort-cironited electric bell or ringer, together withalitou'iatie means for holding the short-circuit open"V during` operation, of the ringer. e

60. A selective signaling systein'coinprieing aline-circuit, a pluralit', of eignalfreceirin'g means connected 'wit vthe said circuit, cach signal-receiving means loing grounded, and a calling apparatus normally 'disconnected frornthe'said line-circuit, but

adapted to be connected therewith for the,

' purpose of selectively operating the :aid

signabreceiving nieans,'said calling apparatue including` a plurality of generators connectedlin. series and grounded at a point between them, together with a. plurality of ringingdreys controlling the vflow of current trom the generators to the line-circuit and cori'cspoiuiling in number to the said signalreceiving ine-ane, at least one of said signal- 'rceciviiner means comprising a normally and locally short-circuited'electric bell or rinvei,

together with automatic Ameans for holding.

the short-circuit open during operation of the ringer, i l

61. A selective signaling system comprising` a metallic line-circuit, a plurality ot' sig# imbrei-ciringr means bridged across' the aid circuit, each bridge being grounded. and a calling apparatus vnornnilly d iscoiinectcd. v t'rom the said line-circuit', but 'adapted to be -tv'onuected thereto for thc purpose of selec-` tively operating said signabijeceiiing means,

` said-calling apparatusl including a plurality" of alternating; currenbgenerators connected lin series and grounded'at a pointbetween them, together with a- )lurality -ot ringingkeys. wliereotl one is u apted for includingl one of Asaid generators in series with the ground and one side ofthe liiiecircuit` an?.

otlferft'or connecting the other side pf the line-circuit' in series with the lfreund and the other generator..4 another for connecting one olt the lgenerators in :i ground-eireuit includintel both sides ot' the line-circuit' in parallel, and the other for conijiectiner hotli generators in series in a complete metallic circuit inclndins.: both .sides ofthe line. at least one of said .eignal-reccviijiug means comprising a ,norm-.illy and Alocally short-virenited electric hell oi" ringer.

62. A selective sionalino' .sw/stein com iri se h l ing;V aJnetallic line-circuit'. a plurality ot' signal-receiving-ineane bridged across the said line-circuit, each bridge being` `grounded 'and including a pairotcondensers arranged at opposite sides ,of the signaLincei-ving means,l und a calling' apparatue'or eelco tively operating the said signal-receiving means over tbe said linevi'ircuitysaid calling 'apparatus including :i plurality of alternating currentirri1eratore connected in series and each. connected with .Q'iound. togetherwitl'i a pluralitxr ot selective ringing-keys corresponding in number to the signal-ri ceirinir means, and adapted for connecting i up. the gencralorafin as many different cir cuits as there are signabreceiring mea-ns, at leastone oi-eaid signal-reccivmer means i- -lz rality of signal-receiving means bridged connected up in grounded, and each signal-receiving means 'purpose of selectively operating Ithe said i signal-receiving means over the ymeans normally renderingr v means for, automatically rendering the bell 'or ringer operative when it is desiredto,

including a vcouple of generators connected comprising a normally and locally shortn 1n series and grounded at a point between circuited electric bell or ringer.

63. A selective signaling system comprising a complete metallic subscribcrs line, a prising an electric bell or ringer, means norsprmg-jaclr in which the said line termimally rendering 'the bell or ringer inopernates, a cord-clrcuit: provided with a plug atlve, together with electro-magnetic means for automatically rendering the bell ringer operative When itis desired to ring the same, together With automatic means for holding the short-circuit open during operation of the ringer.

l 67. A selective signaling system comprising a line-circuit, a plurality of 'signal-receiving means connected With the said circuit, each signal-receiving means being` adapted for insertion in said jack, a plurality of alternating current-generators connected in series and grounded at a point be- A tween them, a plurality of keys for variously connecting the generators with either one or both sides of the cord-circuit, and a plu' across the said line, each bridge being being adapted to be operated by its allotted key and no other, at least one of said signalreceivjng means comprising a normally and loca'll}T short-circuit'ed electric bell or ringer.

'64. A s elective signaling system comprising a complete metallic subscribers line, a plurality of signal-receiving means bridged across the said circuit, each bridge being grounded and including a pair of condensers arranged. at opposite sides of said signalreceiving means, and a calling apparatus normally disconnected from the said line, but adapted to be connected thereto for the lectivcly operating the said signal-receiving means over the said circuit, said calling apparatus including a couple of generators connected in series and grounded at a point between them, and each signal-receiving means comprising an electric bell or ringer, means normally rendering the bell or ringer inoperative, together with electro-magnetic means for automatically rendering the bell or ringer opera-tive Whenit is desired to ring the same, together .with automatic means for holding the short-circuit open duringoperation of the ringer.

68. A select-ive signaling system comprising a line-circuit, a plurality of signal-re- Aceiving'means connected with the said circuit, eachsignal-receiving means being grounded, and a calling apparatus normally disconnected from the said line-circuit, but adapted to be connected therewitli for the 1i u'rpose of selectively operatingv the said signal-receiving means, said calling appa.- Iratus including a plurality of generators said line, said calling apparatus including a plurality of alternating current-generators, together with switching devices adapted for variously connecting one or more of said generators with either one or both sides of the line-circuit, and whereby said generators may be as many diiferent circuits as; there are signal-receiving means, each signal-receiving means being responsive only when its allotted line-circuit is closed, at connected in series and least one of Said signal-receiving means f between them, together With a plurality ot' comprising a normally and locally shortringingkeys controlling the flow of current circuited electric bell orvringer. lifrom the generators to the line-circuit and 65. A selective signaling system comprisvcorresponding in number to the said signaling' a line-circuit, a plurality of signal-receiving means connected with the said circuit, anda calling apparatus for selectively operating said signal-receiving means over the said circuit, Asaid calling apparatus including a couple of synchronized alternating current generators, said generators being connected in series and grounded at a point between them, and each signal-receiving means comprising an electric bell or ringer,

the bell or `ringer inoperative, together With. electro-magnetic means comprising an electric bell 'or ringen, means normally rendering the bell or ringer inoperative, together with electro-magnetic` means for automatically rendering the bell Eor 'ringer operative When-it is desired to .ring

:holding the short-circuit open during operaring the'same. s.

v 66.. A 'selective signaling system comprisinga line-circuit, a plurality of signal-re-v ceiving means connected with the said circuitand calling apparatus for selectively operating the i said signal-receiving means over the said circuit` said calling apparatus them, and eachsignal-receiving means com-4 ounded and a callin@ aunaratus for sc` gr i a:

grounded at a point lr the same. together with automatic'means for receiving means, and each signal-receiving spring-jack in which the with electro-magnetic means ringing-keys including one oi said generators i"n series with the ground and one side ot the line-circuit, another 't'or Connecting the other side `ot the line-circuit in series with the ground `and the other generator, another for connecting one of the generators in a ground-circuit including both sides ol' the line-circuit liii parallel, and the other for connecting both generators in series in a complete metallic.,

circuit including both sides of the line, and each signal-receiving means comprising an electric bell or ringer. means normally ren- :ring the bell or ringer inoperative, together with electro-magnetic means for automatically rendering the bell or ringer operative when it is desired to ring the saine.

'70. .mi selectire signaling system comprising ay metallic line-circuit, a plurality of signal-receiving means bridged across the said line-circuit, 'eacli bridge being grounded and including a pair of condensers arranged at opposite sides et', the signal-receiving means, and a calling apparatus for selectively. operating,r the said signal-receiving means over the said line-circuit, said calling apparatus including a plurality oit alternating current-generalors yconnected in series, and each connected u'itli ground, together ,with a plurality ot selective ringing-keys corresponding in number to the signal-receiving means. and adapted for connecting up the generators in as many different circuits as there are signal-receiving means, and each signal-receiving means Vcomprising an elecmcans normally renderinoperative, together for automatically rendering the bell or ringer operative when itI is desired to ring the same.

T l. A selective signaling system comprising a complete metallic. subscribers line, a

said line terminates, a cord-circuitprovided with a plug adapted t'or insertion in said jack, a plurality ot' alternating current-generators connected in series and grounded at a point between them, a plurality of keys for variously connecting the generators with either one or both sides ot' the cord-circuit, and a plu- 1ality of signal receiving means bridged across the said linel' each bridge being grounded. and each signal-receiving means being adapted to be operated by its allotted key and no other, and each signal-receiving means comprising an electric el lor ringer,

tric bell or ringer, ing the bell or ringer means normally rendering the bell or ringer inoperative, together with electro-magnetic means `for automatically rendering the bell or ringer operative when it is desired to ring the same.

`72. A selective signaling system comprising a complete metallic subseribers line, a plurality of signal-receiving means bridged across the `said circuit, each bridge being codecs whereof one is adapted ",k'or

grounded and including` a sers arranged at opposite sides of said signal-receiving means, and a calling apparatus normally di seonnected from the said line, but adapted to be connected thereto for the purpose of selectively operating the said si nal-receiving means over the said line, salad calling apparatus including a plurality of alternating 4current-generators, together with sir-itching devices adapted for variously connecting one or more of said generators with either one or both sidesof 'the line-circuit, ai 1dW.-hereby said generators may bf!V connected up in as many different circuits 'asv there are signal-receiving means, each signal-receiving' means being responsive only when its allotted line-circuit is closed, and each signal-receiving means comprising an electric bellV or ringer, means normally rendering the bell or ringer inoperative, to-

pair of condengetlier with. electro-magnetic means for autoinatieally rendering tlie bell or ringer opera tive when it is desired to ring the saine.

73. A selective; signaling system com rising a line-circuit, a plurality of signa -recen-'ing means connected with the said eircuit` and aA callingr apparatus for selectively operating said signal-receiving means over the said circuit, said calling apparatus including a. couple of synchronized alternating vcurrent generators, said generators loeing connected in series and grounded at a point between them, at least one of said signal-receiving means comprising an electric bell or ringer, means normally rendering the bell or ringerinoperatlve, together with electro-magnetic means for rautomatically rendering the bell or ringer operative when it is desired to ring the same.

74. A selective signaling system com rising a line-circuit, a plurali. of signa receiving means connected wit! the said circuit, and `calling apparatus .Eor' selctively operating the said signal-receiving means over the said circuit, said calling apparatus including la couple of generators, connected in series and grounded at a point between them, at least'one of saidsignal-receiving Imeans normally renderin vthe bell or ringer inoperative, together Wit electro-magnetic means for automatically rendering the bell means comprising an electric bell or ringer, i

lll]

or ringer operative when itis desired to ring the saine, together with automatic eans'for holding the short-circuit open during operal generators, connected m series and grounded at apomt paratus for selecbetween them, at least` one of said signalreceivmg means comprlsmg an ele'ctric bell or ylringer, means normally rendering the bell or ringer inoperative, together With electro-magnetic means for automatically rendering the bell or ringer operative When it is desired to ring the saine, together with automatic means for holding the short-circuit open during operation of the ringer.

76. A, selective signaling system comprising a line-circuit, a plurality-'of signal-receiving means connected with the said circuit, each Signal-receiving means being pcunded, and a calling apparatus normally onnected from the said line-circuit, but adapted'to be connected therewith for the p urpose o f selectively operating the said circuit open during operation of thel ringer.

77. A selective signaling system comprising a metallic line-c1 rcuit, a plurality of signal-receiving means bridged across the said circuit, each bridge being grounded, and a calling apparatus normally disconnected from the said line-circuit, but adapted to be connected thereto for-'the purpose of selectively operatinglsaid signal-receiving means, said calling apparatus including a plurality of alternating current-generators connected in series and grounded at a point between them-,rte f 1-er with a. plurality of ringingkeys wl'iereot one is adapted for including'- one of said generators in seriesv with the ground and one side of the line-circuit, an-

other for connecting the other side of the luie-circuit 1n series with the ground and the other generator, `another for connectmgrone of the generators in a ground-circuit including both-sides of the line-circuit in parallel, and the other iorvconnecting both generators in series in a complete metallic circuit in-` cluding both sides off-the line, atleast o-ne of vsaid signal-receiving means comprising 4an' electric bell or ringer, means normally ng the bell Aor ringer inoperative, to-

: with electro-magnetic means for automatically rendering the bell. Aor' ringer Voperativewhenit is desired to ring the same.

78. A selective signaling system comprising a metallic line-circuit, a 'plurality of signal-.receiving means bridged across the said line-circuit, each bridge being grounded and including a pair of condensers'arranged at opposite sides of the signal-receiving means, and a calling apparatus for selectively operating the said signal-receiving ringer operative `when it is desired to ring the same.

l 79. A selective signaling system comprising a complete metallic subscribers line, a spring-jack in Which the said line terminates, a cord-circuit provided with a plug adapted for insertion in said jack, a plurality of alternating current-generators connected in series and grounded at a point between them, a plurality of Vkeys for variously connecting the generators With either one or both sides of the cord-circuit, and a plurality of signalreceiving means vbridged across t-he said line, each bridge being grounded, and each signalreceiving means being adapted to be operated by its allotted key and no other, at least one of said signal-receiving means comprising an electric bell or ringer, means normally rendering the bell or ringer'inoperative, together with electro-magnetic means for automatically rendering the. or ringer operative when it is desired tog' ningthe same.

80,. it selective-signaling system con'iprisa ing a complete metallic subscriberlsiine, a plurality ot signal-receiving means bridged lacross the said circuit, cach bridge being grounded and including a pair of condensers arranged at opposite sides of said signalreceiving means, and a calling apparatus normally disconnected from the said line, but adapted to be connected `thereto .for the purpose of s'electiuelyv operating the said signal-receiving means over the said line,

' vsaid calling apparatus including a plurality of alternating current-generators, together With switching devices adapted for variously connecting one or more of said generators with either one or both sides ot' the linecircuit, and whereby said generators may be signal-receiving means being responsive only when, its allotted line-circuit is closed, at

a v least one of said slgnal-receivmg means comprising an electric bell or ringer, meansfnormally rendering the bell or ringer inoperative, together with electro-magnetic means for automatically rendering the bell or ringer operative When it is desired to ring the same.v V

81. A selective signaling system compilsing a plurality of selective signal-receiving means, and a suitable calling apparatus for selectively operating said signal-receiving y nection extendin means, comprising means for supplying ringing current through as many dierent circuits as there are separate signal-receiving means, and eachsignal-receiving means comprising an electric-bell or ringer, a normally-closed shunt or short-circuiting connection extending ringer, and means for autgmatically opening and holding open saidshunt or shortcircuiting connection when the bell isI to be rung. i

82. A selective signaling system comprising aplurality of selective signal-receiving means, and a suitable calling apparatus for selectively operating said signal-receivingP means, comprising means for. su plying ringing current through as many i'erent circuits as there are separate signal-receiving means, at least one of said si al-receivi'ng means comprising an electric ellv or ringer, a normally-closed shunt or short-circuitmg4 connection extendin around said bell or ringer, and means or automatically opening and holding open said,I shunt or shortcircuiting connection when the bell is to be rung.

83. A selective signa-ling system comprising a plurality oi? selective signal-receiving means, and a suitable calling apparatus for selectively operating said signal-receiving means, comprising means for su plying ringing current through as many iierent. circuits as there are separate signal-receiving means, and eachsignal-receiving means comprising an electric bell or ringer, a normally-closed: shunt or short-circuitingy conaround such bell' or ringer, and a re ay having one or more windings connected in series with said bell, said relay being adapted to open and hold open said shunt orl snort-circuiting connection when it is desired to ring the bell.

4 84. A selective signaling system comprising a plurality of selective signal-receiving means, and a suitable .calling apparatus forV selectively operating said signal-receiving means com risin means for su ll in rin a P P g g a normally-close ing current through as many different cir- 'cults as there are separate. signal-receiving means, at least one of sald signal-receivlng means comprisin' an electric bell or ringer;

shunt or 'short-circuiting connection extending around such bell' or ringer, and. a relay havigone or more Windin .connected in series with said bell, said re ay being adapted to open and hold open around said bell orl said shunt or short-circuiting connection when it is desired to ring the hell.

85. A selective signaling system comprising a plurality of selective signal-receiving means, and a suitable calling ap aratus for selectively operating said signa receiving means, comprising means for supplying ringing current `through as manyv different circuits as there are separate signal-receiving means, and each of said signal-receiving means comprisin' an electric bell or ringer, a normally-close' shunt or short-circuitmg connection extending around such bell or ringer, and a relay adapted for opening and holding open said shunt or short-circuiting -connection when the bell is to be rung, said relay having a.;plura1ity of coils each of vwhich is in series with the bell or ringer.

i 86. A selective signaling system comprising a plurality of selective signaling-receiving means, and a suitable calling apparatus for selectively operating said signal-receivingA means, comprising means for supplying ringing current through as many dierent circuits as there are separate signal-receiving means, at least one of said si ,al-receiving means comprisin an electric ell or ringer, a normally-close shunt or short circuiting connection extending around such bell or ringer, and a relay adapted for opening and holding op'en said shunty or short-circuiting connection when the bell is to be rung, said relay having a plurality of coils each of whichis in series with the bell or ringer.

87. A selective signaling system comprising a plurality of selective signal-receiving means, and a suitable calling apparatus for selectively operating said signal-receiving means, comprising means for supplying ringing current through as many different circuits as there are separate signal-receiving means, and each signal-receiving means comprising a normally and .locally shortcircuited electric bell or rinver, together with automatic means for holding the shortcircuit open during operation of the ringer.

88. A selective signaling system comprising a plurality of selective signal-receiving `cans, and a suitable calling apparatus for selectively operating said signal-receiving means, comprising fmeans for su lying ringing 'current through as many i ercnt circuits vas there are separate signal-receiving means, at least one of saidsignal-receiving means comprisin a normally an locally short-circuited e ectric bell ol.' ringer, together with. automatic means for holding the short-circuitl open' during operation of the ringer. l

89. A.A selective signaling system compris- 1neans, and a suitable calling apparatus for selectively operating said signal-receiving -`ringng current through. as many means, comprising `means for su lying', i

dilderent 130 1421sY ing a plurality of selective signal-receivmg 

